Atomic frequency standards (atomic clocks) are some of the most stable frequency references available. Due to the stability offered by atomic clocks, atomic clocks are frequently used in multiple applications that demand stable frequency references. However, high performance atomic clocks have traditionally been relatively large rack mounted or table top devices. Thus, efforts are under way to reduce the size of atomic clocks such as by reducing the physics package of atomic clocks and other sensors which utilize cold atom clouds as the sensing element.
Making the physics package smaller has unique and complex challenges because the physics package must be hermetically sealed, permit the introduction of light into its interior, and be constructed of non-magnetic materials. In certain methods of manufacturing a physics package, a glass body is machined with multiple holes for placement of mirrors and windows on its exterior, and a plurality of angled borings that serve as light paths to trap, cool, and manipulate the cold atomic sample.
In general, a laser cooled atomic clock operates by trapping and manipulating atoms with light beams from one or more lasers and magnetic confining fields generated by one or more conductive bodies. The physics package defines a vacuum sealed chamber that holds the atoms that are manipulated and measured. The atoms within the physics package are trapped within the volume such that the multiple light paths intersect with the atoms from different angles. Developing a small volume physics package which allows for large optical beams and added-flexibility of a multi-beam configuration is important to the development of high performance miniature atomic physics packages. However, smaller size requirements for atomic clocks present challenges for current building techniques.